I've done Beau Rivage. It's not bad....it's kinda like a miniature sized version of a Vegas resort. It was designed by Steve Wynn before he sold all of his stuff to MGM, so it's nice.
http://www.beaurivage.com
Biloxi is a lot like going to Jamaica though....stay on the resort. It gets very bad very fast if you venture outside the casinos. You quickly get a reality check and are reminded you're in Mississippi.
The Beau is more expensive than any of the others, but is the most Vegas-like and nicest of the ones I've seen. Just like Vegas, you'll pay a premium for weekend nights, but thru the week isn't terribly expensive. And AirTran does have a couple of flights from Atlanta to Gulfport when they can scare the live stock off the runway.
Only downside is the place is usually slammed with blue hairs who have arrived on tour buses on their way to/from Branson....